Assignment 1 (A)
CHAPTER 12
INTERMOLECULAR FORCES AND LIQUIDS AND SOLIDS
1- Which one of the following substances should exhibit hydrogen bonding in the liquid state?
A. PH3
B. H2
C. H2S
D. CH4
E. NH3
2- Which of the following substances should have the highest boiling point?
A. CH4 B. Cl2
C. Kr D. CH3Cl E. N2
3- Which of the following liquids should have the highest viscosity at the same temperature?
A. CH3OCH3
B. CH2Cl2
C. C2H5OH
D. CH3Br
E. HOCH2CH2OH
4- Which of the following characteristics indicates the presence of weak intermolecular forces in a liquid?
A. a low heat of vaporization
B. a high critical temperature
C. a low vapor pressure
D. a high boiling point
E. None of the above.
5- Which of the following characteristics indicates the presence of strong intermolecular forces in a liquid?
A. a low heat of vaporization
B. a low critical temperature
C. a low vapor pressure
D. a low boiling point
E. None of the above
6- Which of the following substances would be expected to have the lowest vapor pressure at room temperature?
A. ethanol bp = 78oC
B. methanol bp = 65oC
C. water bp = 100oC
D. acetone bp = 56oC
7- Choose the response that lists the member of each of the following pairs that has the higher boiling point.
(1) H2O or KI (2) HF or HI (3) Cl2 or Br2
A. H2O, HF, and Cl2
B. KI, HF, and Br2
C. KI, HI, and Br2
D. H2O, HI, and Cl2
E. KI, HF, and Cl2
8- Arrange the following in order of increasing boiling point: RbCl, CH3Cl, CH3OH, CH4.
A. CH3OH < CH3Cl < RbCl < CH4
B. CH3OH < CH4 < CH3Cl < RbCl
C. RbCl < CH3Cl < CH3OH < CH4
D. CH4 < CH3OH < CH3Cl < RbCl
E. CH4 < CH3Cl < CH3OH < RbCl
9- Which of the responses includes all of the following that can form hydrogen bonds with water molecules?
1. Na+ 2. CH3COOH 3. C2H6 4. CH3NH2
A. 1, 2
B. 1, 3
C. 2, 3
D. 2, 4
E. 3, 4
10- Which of the following substances would have the highest critical temperature?
A. CH3Cl
B. C2H6
C. F2
D. H2
E. CO2
11- Calculate the amount of heat that must be absorbed by 10.0 g of ice at ─20oC to convert it to liquid water at 60.0oC.
Given: Specific heat (ice)
= 2.1 J/g·oC Specific heat (water) = 4.18 J/g·oC
ΔHfus = 6.0 kJ/mol
A. 420 J
B. 2900 J
C. 6300 J
D. 63 kJ
E. 7.5 J
12- Calculate the amount of heat needed to melt 2.0 kg of iron at its melting point (1809 K), given that: ΔH fus = 13.80
kJ/mol.
A. 494 kJ
B. 27,600 kJ
C. 27.6 kJ
D. 27,600 J
E. 25,000 kJ
13- What mass of water would need to evaporate from your skin in order to dissipate 1.7  105 J of heat from your
body?
H2O(l)  H2O(g) ΔHvap = 40.7 kJ/mol
4
A. 7.52  10 g
B. 418 g
C. 75.2 g
D. 58.4 g
E. 6.92  106 g
14- The vapor pressure of ethanol is 400 mmHg at 63.5 oC. Its molar heat of vaporization is 39.3 kJ/mol. What is vapor
pressure of ethanol in mm Hg at 34.9oC?
A. 1510 mmHg
B. 100 mmHg
C. 200 mmHg
D. 0.0099 mmHg
E. 4.61 mmHg
15- Which of the following gases would have the highest critical temperature?
A. CH4 B. O2 C. CO2 D. NH3 E. Ne
16- The molar heats of sublimation and fusion of iodine are 62.3 kJ/mol and 15.3 kJ/mol, respectively. Calculate the
molar heat of vaporization of liquid iodine.
A. 77.6 kJ B. 47.0 kJ C. ─47.0 kJ D. ─77.6 kJ E. 4.07 kJ
17- Which of the following substances will have the highest boiling point?
A. methane (MW=16)
B. butane (MW=58)
C. ethyl alcohol (MW=46)
D. methyl alcohol (MW=32)
18- Chlorine has a critical temperature of 144°C and a critical pressure of 77 atm. Under which of the following
conditions would Cl2 most likely be a liquid?
A. 125°C, 70 atm
B. 125°C, 30 atm
C. 150°C, 70 atm
D. 150°C, 30 atm
19- The normal boiling point of ether is 35°C. Comparing ether and water, at the same temperature, which statement
below is TRUE?
A. The vapor pressure of both liquids are the same.
B. The vapor pressure of ether is greater than that of water.
C. The vapor pressure of water is greater than that of ether.
D. The vapor pressure of both liquids are equal to the temperature.
20- Indicate all the types of intermolecular forces of attraction in the following compounds.
a. F2(l)
_____________________
b. HF(l)
_____________________
c. SO2(l)
_____________________
d. He(l)
_____________________
21- Identify the INCORRECT statement below:
A. The vapor pressure of liquid water at 100°C is 760 Torr (1 atm).
B. The normal boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals1atm.
C. The boiling point of a liquid increases as the surrounding pressure decreases.
D. Vapor pressure of a liquid increases as the temperature increases.
E. A liquid boils when its vapor pressure equals the surrounding pressure.
21- TRUE-FALSE QUESTIONS
1- Octane, C8H18, boils at 125oC as compared to water which boils at 100 oC. This information suggests that the
dispersion forces in nonpolar octane molecules are stronger than dipole-dipole interactions and hydrogen
bonding in water. T
2- The shape of the water-to-glass meniscus results from the strong adhesive forces between glass and water.
T
3- The fact that the density of ice is less than the density of liquid water is due to theformation of hydrogen bonds. T
4- The freezing point of a liquid does not change as the atmospheric pressure changes.
F